Weird ovulation date change today!

So I’m curious as to why it stated I would ovulate on the 2.15.20 and all day it has been saying that I was at the highest leave for TTC but literally now it’s pushed back by 2 days and saying I won’t ovulate until the 18th. The only thing I’ve been doing is adding my ovulation test and even though it says I would be ovulating on 2.15.20 the test is getting lighter again. It was higher yesterday and the two days before and I noticed since my last cycle and this one I ovulate around day 13-14. I think I ovulated yesterday....but anywho I’m kind of ranting. I really want to know why or what it means for my dates to change on here and I haven’t done anything on the app at all except report my recent ovulation test.